Wes Johnston, AI4PX wrote:
> Since many repeaters use PL tones, I can see how a low tone might get
> in the way of any given PL tone.... 67hz is the lowest PL tone, so
> this "data" could be sent at <67hz. Since we have two power standards
> on 50 and 60hz, best to avoid those frequencies too. maybe split the
> difference at 55hz? or somewhere between 60 and 67 hz? 62.5 might be
> a nice frequency. Of course we have to select a frequency that has no
> harmonic on any standard PL tone frequency.
>> I have yet to understand how the average "joe ham" will inject low
> frequency audio? Perhaps using the 9k6 pin on the mini-din?
>
The 9K6 pin on the mini-din is one of two RECEIVE outputs. There is
only one TX (audio input) pin on the DIN. It's usage/coupling is
switched (on some radios) by menu options for 1200/9600 baud packet.
If present, this option changes the single input from A/C coupled
bandwidth-limited (usually through the same pre-emphasized audio channel
used for voice) for 1200 baud, to DC-coupled wide-bandwidth
no-pre-emphasis directly to the modulator for 9600 operation. Older
pre-processor-and-menu "dumb" radios were hard-wired to one or the other.
--
Stephen H. Smith wa8lmf (at) aol.com
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